1. Field of the Invention
This invention relates to a printing method and apparatus for embedding predetermined pattern signal into color print signals, and printing an image in which the predetermined pattern has been embedded. This invention also relates to a pattern read-out method and apparatus for reading out the embedded pattern from the image having been obtained with the printing method. This invention further relates to a printing method and apparatus for transforming an image signal, in which deep-encrypted subsidiary information has been embedded, into a print signal, and performing a printing operation in accordance with the print signal. This invention still further relates to a recording medium, on which a program for causing a computer to execute the printing method or the pattern read-out method has been recorded and from which the computer is capable of reading the program.
2. Description of the Prior Art
In cases where a photographic original image is to be utilized as an original image for printing, the photographic original image is read out with a scanner, or the like, R, G, and B component digital signals are thereby obtained, and separated plate signals for printing are formed from the digital signals.
As color components of the separated plate signals, four color components, i.e., cyan (C), magenta (M), yellow (Y), which are the three primary colors in ordinary printing, and K for reproduction of a character pattern or a shadow area of an object, are often utilized. Also, where a color reproduction range is wide, or such that a bright image may be obtained, six color components further containing green (G) and orange (O) inks, or more color components are often utilized.
When the R, G, and B color signals are transformed into the C, M, Y, and K color signals (or the C, M, Y, G, O, and K color signals), transform parameters are set such that the original image can be reproduced. In such cases, various parameters for optimizing the addition of, particularly, K are utilized by considering printing stability, the ink cost, and the like.
Photographic original images and printed matter are valuable as creative works and therefore have copyrights. Accordingly, it is necessary to prevent illegal duplication. Also, certain kinds of printed matter, such as banknotes, securities, and tickets, are realizable and should be prevented from illegal duplication completely. However, recently, color scanners and printers capable of forming images having good image quality at low costs, widely available, and the duplication technology is advancing rapidly.
In order to prevent the illegal duplication described above, various kinds of special printing methods particularly aiming at prevention of forgery of banknotes have heretofore been utilized. Examples of such special printing methods include marking paper with a watermark, embedding a UV ink or a metal belt into paper, and utilizing micro-characters.
However, the printing methods described above require special techniques, and limitation is imposed upon print shops capable of performing the special printing methods. Also, the cost of special printing methods described above are high. Therefore, for certain lowcost items such as cheap tickets, the special printing methods described above is not economically viable way to protect copyrights. Also there are few other countermeasures for prevention of illegal duplication.
In the cases of printing of merchandise packages, it is necessary for merchandise control information for quality and distribution to be printed. The merchandise control information includes the date of production, a lot number, a price, and the like. Ordinarily, the merchandise control information is printed as a character pattern or a bar code. However, in cases where the merchandise control information is printed as a character pattern or a bar code, the freedom of package design becomes constrained. Therefore, it is desired that the merchandise control information can be printed as imperceptibly as possible.